Track Tension Adjustment and Wear Management on the CAT 277B MTL Loader

[MikePhua]

The 277B and Its Multi-Terrain Legacy
The Caterpillar 277B Multi-Terrain Loader (MTL) was introduced as part of Cat’s second-generation rubber-track loader lineup, designed for low ground pressure and high flotation in soft or sensitive terrain. Unlike traditional compact track loaders (CTLs), the MTL system uses a suspended undercarriage with torsion axles and a unique “squirrel cage” roller assembly, allowing smoother ride and better traction over uneven surfaces.
Powered by a Cat 3046 turbocharged diesel engine delivering around 82 horsepower, the 277B combines hydraulic power with a wide track footprint, making it ideal for landscaping, forestry, and utility work. Its undercarriage, however, demands precise maintenance—especially in track tensioning and bushing wear.
Symptoms of Improper Track Tension
Operators may notice:

• Knocking or clunking sounds during travel
  
• Uneven track sag between left and right sides
  
• Premature wear on drive lugs or roller surfaces
  
• Reduced traction or derailing in turns
  
• Increased fuel consumption due to drag
  

Loose tracks can cause misalignment and damage to the idler, rollers, and drive sprocket. Over-tightened tracks, on the other hand, increase stress on bearings and reduce suspension travel.
Primary Tensioning Mechanism and Tools
Track tension on the 277B is adjusted via the front idler assembly, which slides forward or backward within the track frame. The adjustment relies on a hydraulic ram or mechanical tool to shift the idler, followed by bolt torqueing to lock the position.
Key components include:

• Dead idler bracket with multiple adjustment holes
  
• Central wedge mechanism that lifts the rear of the machine slightly during tensioning
  
• Lock bolts: typically four ¾" bolts and one central 1¼" bolt
  
• Factory tension tool (often missing), priced around $250
  
• Alternative tools: Porto-Power hydraulic ram or long pry bar
  

Some technicians use a Porto-Power kit from Harbor Freight to push the track frame outward, avoiding the need for the OEM tool. Others fabricate custom jigs using ratchet boomers, though hydraulic methods are faster and safer.
Field Repairs and Bushing Substitutes
The 277B’s squirrel cage roller assembly uses bushings that wear out around 1,500 hours. Original bushings are plastic and prone to deformation. Some operators replace them with PVC pipe segments, which last 500–600 hours and cost virtually nothing. While not OEM-approved, this method has proven effective in low-budget operations.
Bushing part number 199-5332 is priced at roughly $6.80 each, and the full assembly may require up to 48 units. Replacing all bushings during undercarriage service ensures even wear and smoother operation.
Track Frame Adjustment Tips
To tighten the track:

• Loosen only the ½" bolts securing the idler bracket
  
• Leave the large center bolt snug to maintain wedge alignment
  
• Push the track frame in the opposite direction of intuition—the wedge mechanism raises the rear to increase tension
  
• Use two bolts in the adjustment holes to torque the idler into place
  
• Recheck sag after cycling the machine forward and backward
  

If the idler has reached its last adjustment hole, the track frame must be extended further before re-engaging the idler. This ensures continued tensioning range as the track stretches over time.
Preventive Maintenance and Upgrade Suggestions
To extend undercarriage life:

• Check track sag weekly; ideal clearance is typically 1–1.5 inches at midpoint
  
• Inspect bushings and rollers every 250 hours
  
• Replace worn drive lugs before they shear off
  
• Clean debris from the track frame and idler housing
  
• Use high-quality rubber tracks with reinforced steel cords
  
• Avoid aftermarket “Larry lugs” which have poor longevity
  

Some operators keep spare track sets on hand, especially when sourcing used parts from auctions or surplus dealers. A pair of tracks may cost $3,600 or more, depending on condition and brand.
A Story from the Yard
In Missouri, a contractor rebuilt his 277B’s track system using a Porto-Power ram and PVC bushings. After removing the old squirrel cage rollers, he fabricated a press jig to install the new bushings evenly. The machine returned to service clearing brush and grading driveways, with noticeably quieter operation and improved traction. He later added LED work lights and a backup alarm, turning the aging loader into a reliable daily performer.
Conclusion
Track tensioning on the CAT 277B MTL loader is both an art and a science. With its unique undercarriage and suspended roller system, proper adjustment ensures smooth travel, reduced wear, and extended component life. Whether using factory tools or field improvisation, understanding the geometry and mechanics of the tension system is key. In the world of multi-terrain loaders, tension isn’t just about tightness—it’s about balance, longevity, and keeping the machine moving forward with confidence.